Filter-pad and method of making same.



No.f'40,36'7. PATENTED SEPT. 29, '1903.

E. M. KNIGHT. I

FILTER PAD AND METHOD 0F MAKING SAME. APPLIGATLOH FILED MAE. 4.11903.

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UNITED STATES;

Patented September 29, 1903.

PATENT OFFICE.

EDWARD M. KNIGHT, OF BROOKLYN, NEW YORK, ASSIGNOR OF ONE-HALF TO R. H.MARTIN, OFNEW YORK, N. Y.

FILTER-PAD AND METHOD OF MAKING SAME.

. t SPECIFICATION forming part of Letters Iatent No. 740,367, datedSeptember 29, 1903.

Application tiled March 4, 1903.

To all whom it may concern:

Beit known that I, EDWARD M. KNIGHT, a citizen of the United States,residing at Brooklyn, in the county of Kings and State of New York,haveinvented new and useful Improvements in Filter-Pads and Methods ofMaking the Same,'ot` which the following is a specitication.

This invention relates to filter-beds, and particularly those employinga fibrous pad for separatin g sedimentary matter from water designed fordrinking or domestic purposes; and the invention consists, essentially,of a filter-pad formed of fibrous material having the greater portion ofits body compressed to make substantially a dense and yet sufficientlyporous body through which the Water percolates and during its passage isrelieved of the suspended or sedimentary particles, said pad having asurrounding edge of less density than the remaining portion andsubstantially uncompressed, whereby the edge may be turned at an abruptangle without danger of breaking the pad at the angle or bend or sodisturbing the fibers as to open up crevices for the possible leakage ofunltered Water.

Myinvention further consists of the method of making the aforesaid pad,said method including the steps of placing a mass of fibers betweensurfaces which have a greater thickness or elevation at the centralrportion than at the edges and applying pressure to cause the surfacesto compress and make more dense and compact the middle portion of thepad and to leave the edges substantially uncompressed and the fibersthereof substantially loose. Y

In the accompanying drawings I have illustrated one means for carryingforward my process, and wherein- Figure l illustrates a verticalsectional view of a holder and opposing dies or surfacesbetween whichthe loose fibers are compressed. Fig. 2 is a plan view of one ofthe diesremoved. Fig.` 3 illustrates one of the complete pads.

In carrying out my invention I prefer to use as the material from whichthe pad is to be made asbestos bers, which because of their insolubleand indestructible character Serial No. 146,123. (No model and theirpeculiar property of forming a soft seemingly-slimy bed when saturatedforms a mostedective substance for the filtration of fluid matter. Thesefibers are carded or otherwise combed or loosened, vand a vsufficientmass-determined, for instance, by weighing--is placed within a suitableholder and subjected to pressure to condense the mass and form ailexible pad that may be handled without danger of its being easilybroken or injured. A holder well adapted for the purpose is shown at A,said holder having an opening a in its bottom to facilitate the removalvof the dies and pad after compression has been completed.

Upon the bottom of the holder is rst placed a die B, of metal or otherappropriate material, said die having a thickened or raised portion b,soas to leavea surrounding outside portion of less thickness. Over thisraised ,face of the die and also extending over the reduced edge portionis a piece of fabric c, the edge of which may be confined by bend-v ingthe edge ofthe die over it to form a binding-strip, as shown at d, butthe combined thickness of which folded edge will still be less than thethickness of the raised central portion of the die. f

The fabric surface of the die is irst moistened with water, and the dryloose asbestos Iibers are placed Within the holder upon this moistenedsurface, and a second or upper die C of the same construction as thefirst-named die and having its fabric-surface c' moi'stened is nowplaced upon the mass of bers and the holder and its contained diesplaced within a suitable press (not shown) and pressure applied to causethe dies to compress the interposed mass of bers to any desired degree.l

As the central portions of the dies are thicker than the surroundingedge portions and stand beyond the plane of the latter, it will .be

`manifest that when the aforesaid pressure is loo little or nocompression but will have its bers left substantially loose. Furtherthan this, the pad itself will show, as in Fig. 3, a decided bead e atthe junction of the compressed central portion with the less compressedand soft and pliable edge portion, which enables this latter edgeportion to be turned or bent at one or more sharp angles to the moresolid central portion, as when putting the pad into a filter-frameand'bending the soft edge to form a water-tight joint with said frame.

When the pad has been compressed, as before stated, the dies and pad arereadily removed from the holder by pushing the finger or a tool or otherdevice through the hole in the bottom of the bolder, and thus liftinglthe dies and pad, and the dies are then lifted from the pad, theirmoistened surfaces having prevented the fibers sticking to the fabric ofthe dies, and packed in boxes or packages ready for use in filter-framesof suitable size and form.

By the method described I am enabled to make an effective,easily-handled, durable, and comparatively inexpensive pad which iscapable of making a water-tight joint in its frame when in use, andwhich will thoroughly eliminate sedimentary matter from Water and otherliquids.

Having thus described my invention, what I claim as new,and desire tosecure by Letters Patent, is-

1. The method of making filter-pads consisting in subjecting a mass ofdry fibers to pressure and proportioning the pressure so that oneportion of the pad is compressed to a greater extent than the remainingportion.

2. The method of making lter-pads consisting in subjecting a mass of dryfibers to pressure and compressing'the central portion of the pad to agreater extent than the surrounding edge whereby the said edge remainssubstantially soft and pliable.

3. The method of making lter-pads consisting in subjecting a mass of dryfibers to pressure between moistened surfaces, and proportioning thepressure so that the central portion of the pad is compressed to a lessthickness, and made more dense, thanv the surrounding edge.

4. The method of making filter-pads consisting in subjecting a mass offibers to pressure between moistened fabric surfaces, and offsetting thesurfaces to cause them to compress the -central portion of the pad to agreater extent than the surrounding edge and to leave said edge soft andpliable.

5. As an article of manufacture, a filterpad of fibrous material havingacentral portion of less thickness and greater density than theremaining portion so as to leave a surrounding'pliable edge of softsubstantially uncompressed fibers.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

ED WARD M. KNIGHT.

Witnesses:

WALTER J. SKERTEN, GEO. J. B. FRANKLIN.

